1. Field of the Invention
The present invention generally relates to a spool braking device. More specifically, the present invention relates to a spool braking device for a dual-bearing reel that is used during casting and is configured to brake a spool in an electrically controllable manner.
2. Background Information
Conventional electrically controllable spool braking devices have a spool brake unit and a spool control unit, which is configured to electrically control the spool brake unit. (See, for example, Japanese Laid-Open Patent Publication No. 11-332436.)
In this spool braking device, the spool brake unit has a plurality of magnets, a plurality of coils and a switch element or microprocessor. The magnets are mounted around an outside circumference of a spool shaft on an outside of the spool. The coils are arranged radially such that the end faces thereof face toward the radially-outward-facing sides of the magnets. The spool control unit is configured to identify a peak time during which the spool rotates at a maximum rotational velocity and control the spool brake unit based on the identified peak time.
In this spool braking device, the magnets are arranged around the outside circumference of the spool shaft on the outside of the spool and the coils are arranged radially such that the end faces thereof face toward the radially-outward-facing surfaces of the magnets. When the coils are arranged in a radial pattern, the dimension of each coil in the axial direction of the spool is not particularly large. However, the radial arrangement of the coils causes the surface area of coils in a plane perpendicular to the spool shaft to be large and, thus, causes a dimension of the reel body along a diameter of the spool shaft to be large, thereby increasing the size of the dual-bearing reel.
In a spool brake device presented in Japanese Laid-Open Patent Publication No. 2000-217478, a spool brake unit has a plurality of magnets, a plurality of coils and a switch element. The magnets are fixed to an internal circumferential surface of a tubular bobbin trunk of a spool. The spool is mounted in a freely rotatable manner on a spool shaft. The coils are mounted to the spool shaft so as to be spaced from one another along a circumferential direction. The coils are arranged such that they can face the radially-inward-facing sides of the magnets. The switch element is connected to both ends of the coils. A spool control unit is configured to control a braking force by controlling an on/off status of the switch element. More specifically, the spool control unit detects a tensile force acting on a fishing line based on a change in rotational velocity of the spool. The spool control unit brakes the spool by short circuiting the switch element when the tensile force becomes equal to or smaller than a prescribed value.
In this spool braking device, the magnets are arranged on the internal circumference of the tubular bobbin trunk and the coils are arranged on the spool shaft so as to be positioned radially inward relative to the magnets. Since the spool brake unit is arranged inside the tubular bobbin trunk of the spool, the dimension along a diameter of the spool shaft can be made smaller than in the spool braking device described in Japanese Laid-Open Patent Publication No. 11-332436. However, in the case of a dual-bearing real having a spool that has a small-diameter tubular bobbin trunk, a spool brake unit that is arranged inside the tubular bobbin trunk of the spool cannot be used because there is not sufficient space to arrange the spool brake unit. Thus, in such reels, the spool braking unit must be arranged on the outside of the spool in the manner of the spool braking device described in Japanese Laid-Open Patent Publication No. 11-332436. When the spool braking unit is arranged on the outside of the spool due to the tubular bobbin trunk being small, the dimension of the reel body along the axial direction of the spool becomes large and, again, the size of the dual-bearing reel increases.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved spool braking device that limits the increase in size of the dual-bearing reel when the spool braking device is arranged on the outside of the spool. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.